SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b99db81c6578d87c1cc5ed528b3aaab87085ae881f8a41a75acd08dd05779186' 
  AND token = 'QBk2tlo5uZERi+IhHrcOEb0WtFpSdCkJMpauUY0ZqkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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