SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5de91f1f9685b12df5d056109f8f9a63010fbe9420a4a37ea0ad1b008ae832b5' 
  AND token = 'JqLukU92aCCNqj1hOCcsa5TJ8Kt7hojQqGmm5XEPG4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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