SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ab342409b1eb84fa172d46a5b6833955c21bda98d37e46721c33c550be842f6' 
  AND token = 'nsz74RuErVYV1kNGPIJXEO01ECexkFI8Jc3tJitq69s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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