SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c96b624986704b1275c594233959d86147f51a294e2a66bd666f64dd58167676' 
  AND token = 'DKTpAj50QpdsKuS+9LMlByRU5+5aAcytOZY3mBjghxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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