SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c936833c691559b845d8fda54ba55f47d585b2deca3867fc1735addc42c1618f' 
  AND token = 'BfYeXNzG4avjeQGziguNaKgmZ8It0qvu2xGQG+aaKWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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