SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c47f27e6eed0d2615746df74d7227403350786b515db39cfd91bdd8990f4b64e' 
  AND token = 'Gs5QZDGv3NNBQhD0p/tnuNx/pGMEIjdQqZWY40pVJV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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