SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1eab32b3bfccd79cff66d9d9631e4c98cbc80a27b6796f78d379db958033726' 
  AND token = 'MG6jsvidT2jDqOAXXMiEdWKDztujeiyXY5wjE6q3iLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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