SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f5da44273ebbee073bb72ea5b0325e18cf7deaebbf3caa9681e0ac7a79d5170' 
  AND token = '3JjCdGRtW1ETAr85NfDxJ1A+g83XPJZlrJ4OS4IEvqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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