SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7180e9d6519c17a811999b6df2e976bfe46081edf2de1bc51167af786c148c0' 
  AND token = 'FCOEXFq5Itu5/4J/Tdui0orLJRFJfVtGW94RA0p6VW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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