SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'eac8861f06783464e2a1c6988b151122f1005d9b4359d3b31255226a64f1c50d' 
  AND token = '/oQE51jbvbXWKU1UExCWWEJkzYbGvhhrUygFJtGvH2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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