SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4900d9688f6936b6bc63ad16d4af3cb81064278e1822b55005754e201f0371d7' 
  AND token = 'zBJwQjkXYIk3uaGqNdZQnBcgFCr+zmzo69r+coiCcL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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