SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3871acfacc880b410bab1800f03bb17216dedf9294b2dc470dcfc28359a01bac' 
  AND token = 'zFqdJyBBhwic0cq6ktHScNkHyGczqnPizNUqbxmSZLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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