SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75ba3206b43da2865cb27ed458aa3b491060bc809525088116f92f6348117d26' 
  AND token = 'zW8YNKy2OgrN1N9590xZBYabdLMU+/tYSHKqgAkhWoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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