SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c79a3b06c5b253a4ce5442b3418a0e61788f4dee925097e40bbb26c7197708b6' 
  AND token = 'nnZRiSBMUhFM0qrTStN6nLDgktgYOjukfcoEY3mY3no=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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