SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af940c04b8cffb26a6a2d211096f334feff57096a5463b4c64dcf21b84fabdc2' 
  AND token = 'wF8OaLwttQp787xtmbuyFg+bfdrZTxkTDFmyp2LO1r4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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