SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b552e6c2b7fe190715dede981e2140e4a127fb85d9a2c8033defa87b5f295bff' 
  AND token = 'KgXEUNk/VOfOQuKTD9kDvaeORpOPPQSTAQsnfiSjr88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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