SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a5d60142256dcbd66b07b4d2ee77b83727257e0509426a03237cf563ac78d14' 
  AND token = '97QkdpNAOaPRduarFLmbQ15L8eAqhQVEsCmtTR4OsrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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