SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c10fa59d48ad6ab7f3fc3a9e7cab1998408d9e36cdac5bef18cff160bccf40c' 
  AND token = 'z7v+PljPlIuEbvTPRimlM5LbTngDRHGhYVPN2rkIuyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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