SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4f57c1aec75432379b50167dadaa6bccf26d21abd3caf53aed438ba87b4711e' 
  AND token = '5RTv/EKTf+wJGLVZo9bbdMwYH83WPkrhkzBmm4QhSys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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