SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6ff03df25591a86873b68bb9322716bd10c315a75e41a366cd500db1959a65d' 
  AND token = 'RnygJ7Q/bIMHZ+gEzKReGy+yWggte1aw0M/P4+asIYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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