SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaab4b291c95aeb0cbd789ec24f960b49580dc9832445a6b88e37bf0e11070f8' 
  AND token = 'K41wiH/TERlkjrRhdnG5znF6wGasMAoZIuQbavceYkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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