SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b65954090e9bf7f688934ec93d314124fa78e7636721f1631a7947e93f6530ed' 
  AND token = 'raQNiNB9Io9BrHLpvTudMLMFOsgRm739hEBatcJ38t0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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