SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2552ed3b4c07e673cf0286aab3b752dc7936165624a9503e1b9ec27debe6fa0e' 
  AND token = 'iciXtGtDVXluPlAyaReki03JSyndTdrvkLrT9k/uP6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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