SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa440a04aeeb70ab784e789490e65e72d74caac21672822d518b80dc0bb252f6' 
  AND token = 'G4QtH9+P2pscqkTPUmDHSCOosrytnLPx68NIxGycrbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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