SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9fccae53cd7fa08075f441e7624c67780d524c6d987569cfc941b4d20fba1b0' 
  AND token = 'QzQ6qsYyVHauoFJ7POV0QuSFLFJHyMRqpH/ogNpt/JQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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