SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b81f6369e8e873432826bdc1140cf44d9e02bb815b0ff1830d9e6a0523cab125' 
  AND token = 'QEpdjmt2D0ff4jc8hdSW2YkzxqF+jGnAoNgzctVevrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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