SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6521024186dcaf8c948065b42cd4a6c0fcf3e87f2a449171622baeff5ed238db' 
  AND token = 'k1CpJosMyAGzxtHcRo7NuGfeenfryKEAcSh0AaKn/lQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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