SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77cc9865da7454336685d40bc5053c0819dc7273012c487ffa710c4bf5ddaa9e' 
  AND token = 'lkxcSZyjerhTNgskbk9Fmss3PRz6VU2V6MyF8nUvlE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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