SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f86f649112128dad7cbcaee0c44958953431552e2516387fca13fefa4244c39f' 
  AND token = 'LQBC4uLk/V+xg4vhcc4HSkKqXTXJkqk+JCheu1agEhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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