SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0c31c666600784e72bc8e1ea4dda76ea51878970ddcf40bf96193ece14a9809' 
  AND token = 'Ddz7IyszgTLf2xcrVCDG29967k3cpQY1MxBY9Kh8EHw=' 
  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"
    }
  }
}