SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56f707eff5c1c5f953b0acac9fdcf4bccac4bb217440400af694180a60cbd53a' 
  AND token = 'eaYYfq7WK+rnWlf3VDInRGGUBeQLbEUcgikUIp5bxtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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