SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cda511c7b696cfbe08f8bfd448ddf66c8233c3c605891d5c869ee51fa0c3ce74' 
  AND token = 'k6oSzfXRgqzbGbLvCuvXZrc6eqQnBcZ2RAo7us2gqb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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