SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6999dab4e094c8961edc3d494f01bcb9fd43c1f462b047fcc1268da97861fd0b' 
  AND token = '8duuwlxWi+CoJF/+3iNPMZskcvargYfeMYpm5WVgenA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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