SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cda95b15109ff36e9f6b33980d5f62e9e3482c6a060b522adb7bfdc45b98e83' 
  AND token = 'B4yf+/ATHb9rTzkHxZZ1Tq0uDIRCUlS8OnOqwrZgH2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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