SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6485b4dc1d3e898d22fe51338185c1fa30e9e35bc5721d8987dad447ad0ce5a8' 
  AND token = '+WE9r9ByMaNfB1Y3l1RoHTzDoDJcPDfbtZr3MTaeSR8=' 
  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"
    }
  }
}