SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2fe0220b1cec90122625ee4a34272449f5679690aad022ce57e8c3b1dccce561' 
  AND token = '/9ealvGnftTKbWgdB7HrWGNVh+pWjdVD1jKQicWJvWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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