SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c142de8c31d337f87bbb16eba79930c173edbdff974c8fa29219225131ad66f' 
  AND token = 'aea4V2yHSuaN64HNkNtRgzzyU0cPKYDmr+EIlwlB3J4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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