SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7bc093a731506b2419536a15dad2e99fac0823e6a0cb0bab6780d9463cde772' 
  AND token = 'UmnD5Y3rM/clfiudreGz3AxOR2PTF+hRam7lfWZY6mI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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