SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd94c5b5e55f1f2762d56782953deec10d0b5fa92c565609275c80f9daf42dd08' 
  AND token = 'uCo/TcRWD2WvMLQ4pusM0sH+66a35JTWE0uYK6CEaoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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