SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad2e4fd0eed27e459292f90306141e141963d78de8b1cf464dc3b97254d32dfd' 
  AND token = '1MyfS1MJnlA72cV40Bpy2sKqlLBS2260g+Ep3oGJqsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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