SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5386251295888585c2e3b4076eb2d32dee2acd525f892c0f78d1da248d3f23a' 
  AND token = 'hPohCDK/j+RSsoj12ASLiORHodBDBnpHBP2+YXIlypQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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