SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acf2ce23b43e35df3abcc5db5670cbd7e45b56f02a279084c69fcf81a1a5f916' 
  AND token = '8diZCuJBWNV2n4TFaizMV7eDEasbSpA5gOGQ+nKHzbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}