SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a953600b334378dba57f4814142e7d1d1b1f6931bba0866cf0962a1f5c263566' 
  AND token = 'LoTLtSqDM/fuPvOaivFchVUNBPou19K6qBzwDctjflo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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