SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '457d237420fce0914d426e9729ce5103d33dd888f2c1f44d256110613fc71e01' 
  AND token = 'iSULCLVcT9RmVXFEojOyNkH5RelaLN3KmQvTrPRAd80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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