SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4d9375e2dba69610c95a197731920f8281d4d032f8bec64ba663091b2a58a15' 
  AND token = 'NiVOgtwoRJUBKk6E6ZuhVgj4MVKkbmwwaVMoxXbn7Ds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}