SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9f8f3c1235e5ca37f1276cc960aabdef44a43cf1324f31ebcb30f5cff97a093' 
  AND token = 'WqimavvEoEHCYzpkFz11NV/sf0JV1Xme/M1wcYtYKLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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