SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a16c73df8045e1ae8bd2bd2356cc58472de4212f6b3e4635d469023f07ae7790' 
  AND token = 'rsLsoXIkohNh3DPwTaASbtBGrCDJs4Cqr3gekzqdNd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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