SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f4b90dcdd4b36d1dcbd7f92cdb0b06d6db1f09fcbf39440b656bdef2d84f8e5' 
  AND token = 'GcdH+i9Ph++vrdKz7vxhmWe7dsTQHWSLbqHCnD1GCY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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