SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e15e0d463758555d80fc779b69c1ec3847d01a73bfc140fa81f0ccdeb623ab85' 
  AND token = 'GTGfknCDfyCB0M6emb9GP6NERH9cpZr5ABmtSBUo6es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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