SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a623b1916f5ef448e30bfd75dd86f07557220791e94588f8f56ce84c7966562b' 
  AND token = 'WvNSrlGou4tclLVgZPu+eDGzcjUw7iZf9tB7OG86NF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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