SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53d5069740efed28efb5836d695f56355b650d05145ff4248077496354196f3b' 
  AND token = 'HWLYO8q2C+IpipcIh0gzyGTd8UQLm+x9Up3wmkqyqvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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