SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5b3d1da93468dfc8bdbaae6820e3082826c5a6063df69b3c488f36018a4ad6a' 
  AND token = 'Okdr512qF6Cqnf0kFqgMxvgDMAiXNtkaFEk/5oqhZCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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