SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd76d9ae8d4de63294677c5d89ee879fff32572e3f18f8f29395abfb5277a73c' 
  AND token = 'Uf06n4t4JVzMPputC+Jz+JGxgaOXQwMOrpClQtmRNDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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