SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27ce72763812077cb90c8db01c2d7858cd1ddefaa754e03ba4e71d82ac8289fa' 
  AND token = 'n9lBFb+Cf9IOcJxA5edPdkNkAexAtsnHpSvmSVowWLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}