SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32e0bdf690996e451489676584751e74a82170f455e58261b3aad63de099be8b' 
  AND token = 'nZmoZbFJEnzxw1xZ4y02s6P27lBXOGxgXhF0SsFcV/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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