SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd74b43a14f84da84ebbef0020cf44454cd10e041b0784bee6d0ea28c9562c101' 
  AND token = '5toE7yXt13nDYbpwFnClHabikNXIID1PdDQh+/AH3cw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}