SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fab28f69dfdc872b177b0777645e6a21a1e71c3999abd83e0c7e7e4f93f432e' 
  AND token = 'KQUNKBX1Vp2VnibtX+Q6CTctMpelCyTllO4UUQ5Rct4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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