SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '476e0881170bf10115ad0d38483ac14ed12ee0b01e35cf97b145e3527710beab' 
  AND token = 'CBUN70MEi1vb4NPB1QeW1tNknb/3jiqOIyCrNhpesA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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