SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c8240d0b887e005fa9e9416fd1185a6fdde87c75beaa609953e44b474f5bfcb' 
  AND token = '1fWJUYmUIkSnPnZckFTmWhNRZgLdNjpzt/KwMVKw6HE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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