SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1694dbcf152f34ce02fa4604a26d8ff11b67c7ab3e7f9cf510846d769f947e5b' 
  AND token = 'K5PtH/+5hbj2CwgSoJ+TRUxFGt4XKM/T4jIErL9+82k=' 
  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"
    }
  }
}